[spelling] existance to existence

chromeos/system/statistics_provider.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROMEOS_SYSTEM_STATISTICS_PROVIDER_H_
 #define CHROMEOS_SYSTEM_STATISTICS_PROVIDER_H_
 
 #include <string>
 
 #include "base/memory/ref_counted.h"
@@ skipping 80 matching lines @@
 // This interface provides access to Chrome OS statistics.
 class CHROMEOS_EXPORT StatisticsProvider {
  public:
   // Starts loading the machine statistics. File operations are performed on
   // |file_task_runner|.
   virtual void StartLoadingMachineStatistics(
       const scoped_refptr<base::TaskRunner>& file_task_runner,
       bool load_oem_manifest) = 0;
 
   // Returns true if the named machine statistic (e.g. "hardware_class") is
-  // found and stores it in |result| (if provided). Probing for the existance of
+  // found and stores it in |result| (if provided). Probing for the existence of
   // a statistic by setting |result| to nullptr supresses the usual warning in
   // case the statistic is not found. Safe to call from any thread except the
   // task runner passed to Initialize() (e.g. FILE). This may block if called
   // early before the statistics are loaded from disk.
   // StartLoadingMachineStatistics() must be called before this.
   virtual bool GetMachineStatistic(const std::string& name,
                                    std::string* result) = 0;
 
   // Similar to GetMachineStatistic for boolean flags.
   virtual bool GetMachineFlag(const std::string& name, bool* result) = 0;
@@ skipping 20 matching lines @@
   static void SetTestProvider(StatisticsProvider* test_provider);
 
  protected:
   virtual ~StatisticsProvider() {}
 };
 
 }  // namespace system
 }  // namespace chromeos
 
 #endif  // CHROMEOS_SYSTEM_STATISTICS_PROVIDER_H_